The information age has changed the way in which people conduct business. In the early history of the country, the ability to exchange information was limited by the old letterpress-type of printing press, the capability of the United States Postal Service, and personal messenger services. Technology such as the telegraph and telephone eventually allowed corporations and people to more easily exchange information over long distances. In modern times, the evolution of computer technology is revolutionizing both business and the ability to exchange information by allowing people to easily communicate around the world.
Today, businesses are constantly finding new uses for computers. The reason for this phenomenon is two-fold. First, more people are learning how to fluently use computers; second, a growing number of consumers are getting access to their own personal computers (PC).
Many of the new uses that businesses are implementing require computers in remote locations to communicate with one another. Current examples include transferring information from one computer at one location to another computer at a different and remote location; allowing employees to communicate with one another through electronic mail, even if the employees are at different geographic locations; allowing customers to purchase goods and pay bills from their home computers; etc. Additionally, individual people are using their personal computers to shop, pay bills, and access databases with large amounts of information such as consumer guides, magazines, and stock market information.
A modem is the device that allows one computer to communicate with another computer and thus is an integral link in the communication system between two computers such as a PC and a main frame computer. The difficulty is that a single main frame computer may need the capacity to simultaneously handle hundreds of different users that are located in remote locations, and a single modem is required for each communication link. Therefore, a single main frame may require hundreds of modems.
As a result of this need, current technology provides the ability to place a plurality of modem cards on a rack and connect the rack to a single main frame computer. An example of such equipment includes an MT1432MR MultiModem card, which includes three modems. An example of a rack is the CC4800 MultiModemManager rack, which can support up to sixteen MultiModem cards. Therefore, each rack can support up to a total of 48 modems. Additionally, up to 254 racks can be networked so that a total of 12,192 modems can be connected to a single main frame or computer network. This equipment is manufactured by MultiTech Systems, Inc., of Moundsview, Minn.
The rack also supports a controller card that interfaces between the network of modems and a single manager PC. An example of such a controller card is the MR4800 rack controller module also manufactured by MultiTech Systems, Inc. The manager PC and controller card permit a technician or systems manager to track usage and various other kinds of information relating to the modems. They also allow a technician to automatically configure the modems without having to manually set each modem.
However, there is a shortcoming with the present technology. Large systems that use a large number of modems are running 24 hours a day. Thus, technicians cannot shut the system down in order to perform repairs and maintenance, and modem cards are removed and inserted while the system is running. This action is called "hot plugging" modem cards. Hot plugging modem cards causes random characters and a great deal of noise to be transmitted to the controller card. As a result, the modem card may receive packets that contain errors. The difficulty is that there is not presently any way to determine whether a packet contains an error, and any faulty packets will be processed and forwarded to the manager PC, a potentially devastating result.
A faulty packet may cause a modem configuration to be incorrectly set or incorrect information to be recorded at the manager PC. These type of errors can cause additional difficulty for a technician who is troubleshooting the system. Moreover, a system manager may have faulty information by which to record and analyze the usage of the present system. This faulty information will cause difficulties in managing a computer system and forecasting future growth. The ultimate result in either of these scenarios is difficulty for the user who attempts to access the host through a remote PC or terminal.
Thus, there is a need for a fault tolerant system, apparatus, and method for transmitting a data packet. More particularly, there is a need for a system, apparatus, and method that is able to determine when a faulty packet is transmitted so that the receiving end will not accept the faulty packet. There is also a need for a system in which modem cards can be hot plugged. When applied to modem technology, such a system, apparatus, and method will prevent faulty information from being sent to the manager PC and will prevent a modem from being incorrectly configured.